1. Field of the Invention
The present invention concerns a device in connection with a separator in a processing plant, for example a plant for processing a fluid consisting of oil, water and/or gas, comprising a container or separation tank for separation of the various phases of the fluid, an inlet arranged in connection with the tank and two or more outlets.
2. Description of Related Art
Separators designed to handle large variations in liquid quantity will often have a large distance between the inlet and the normal liquid level. The inlet often generates large drop quantities and the rate of fall of the liquid creates further drops when the liquid meets the surface of the liquid in the separator. In such separators it is often important to reduce the volume taken up by internals to a minimum so that the volume available to buffer (cushion) the liquid is at a maximum. It is therefore important to reduce the drop formation at the inlet, the rate of fall of the liquid towards the surface of the liquid and the volume of the internals in the separator.
French patent application no. 9007622 describes a procedure and device for the separation of a liquid, for example oil and water, in which the two phases are introduced into a vertical, cylindrical chamber and a helical part inside this chamber, of which at least one side consists of a helical surface. This solution works as follows. The coalition of the dispersed phase of oil and water takes place on the surface of the internal screw by the liquid to be separated being exposed to a rotational vovement as a consequence of it flowing downwards along the screw. The purpose of such a rotational movement is to utilize both gravitational force and centrifugal force to achieve effective separation. The light phase, the oil, will flow inwards towards the chamber""s (screw""s) axis and upwards, while the heavier phase, the water, will flow downwards towards the base of the chamber.
This prior art solution is expensive to produce and has low capacity. Moreover, the presence of any gas in the fluid to be separated seems to disturb the separation process and will thus reduce its efficiency.
The present invention concerns a device in connection with a separator in which it has been possible to reduce the drop formation at the inlet, the rate of fall of the liquid towards the surface of the liquid and the volume of the internals. The present invention is able to handle large flows, main flows of oil/water and any sub-flows.
The present invention is characterized in that the fluid to be separated is designed to flow via a spiral duct which extends from the inlet down towards the base of the container.